Calculate checksum for Laboratory Information System (LIS) frames

Question

I\'m developing an instrument driver for a Laboratory Information System. I want to know how to calculate the checksum of a frame.

Explanation of the checksum algorit

Answer 1

Finally I got answer, here is the code for calculating checksum:

private string CalculateChecksum(string dataToCalculate)
{
    byte[] byteToCalculate = Encoding.ASCII.GetBytes(dataToCalculate);
    int checksum = 0;
    foreach (byte chData in byteToCalculate)
    {
        checksum += chData;
    }
    checksum &= 0xff;
    return checksum.ToString("X2");
}